The present invention relates to hose joint assemblies, e.g., connections, branched hoses and bleeding devices for fluid circuits, and especially to such assemblies for use in automotive and industrial coolant circuit assemblies and to processes for manufacturing such assemblies.
Hose joint assemblies, and in particular such assemblies used in fluid circuits for automotive and/or industrial processes, operate in exceedingly harsh environments. Factors including varying pressures and temperatures at different points of an assembly, varying diameters of different hoses in a particular circuit, as well as chemical exposure result in the need for highly rigorous hose assemblies. For these systems to operate effectively, the connections between the hose and the inner connection members to which they are sealed must be fluid tight and must be able to resist separations caused by fluid pressure. This mode of separation is known as blow-off Separation of the hose from the fixtures may also occur as a result of environmental interference, which mode of separation is known as pull-off.
A branched rubber hose is a difficult article to manufacture in great numbers with efficiency and economy, and many previous attempts at manufacturing such assemblies have resulted in products that were not entirely reliable against leakage in use. Known hose joint assemblies generally include rubber hoses, the end portions of which are sealed to generally rigid inner connection members by means of a sealing mechanism. Three types of sealing mechanisms for connecting the rigid inner connection members of such assemblies, e.g., those in the shape of T's, Y's, X's, elbows and so forth, to the flexible hose components include metal clamps, shrink bands or clamps, and molding techniques.
Metal clamp-type sealing mechanisms suffer from a host of drawbacks, including a susceptibility to corrosion, a susceptibility to pull-off and difficulty of installation due to clamp protrusions, and a susceptibility to blow-off due in part to the compression set of the materials and the inability of the metal clamps to respond to such dimensional changes. Shrink band techniques, wherein polymeric bands are placed about the connection points of such assemblies and allowed to contract resulting in a compressive connection, generally address the corrosion, pull-off and installation problems associated with metal clamps. The additional logistical and manufacturing steps and costs associated with forming and storing the shrink bands however makes this technology relatively expensive. Molded sealing techniques, wherein a thermoset or plastics material is molded about the connection point of an assembly and is cured or allowed to harden, resulting in a compressive type seal about a hose connection point, eliminate the additional steps and costs of manufacturing and storing bands. In this method, the seal about the inner connection point is formed directly on the joint assembly itself; molding material is formed in such a way as to essentially encapsulate the inner connection member and hose ends. But this method is still somewhat burdensome; relatively large amounts of molding material are generally used to encapsulate the entire joint portion of the assembly, and where such material is reduced to save on costs, the integrity of the seals or the stability of the assembly is generally compromised.
Various prior attempts to reduce the cost of such molded hose joint assemblies without compromising the integrity of the seals or the stability of the assembly have met with varying success. One attempt involves the elimination of a portion of the molding material required to encapsulate a joint assembly via the use of permanent external runners or external bridges which connect one band about one hose connection point with another band about another hose connection point. External runners or bridges between hose connection points allow molding material to flow during the molding process from one hose connection point to another without encapsulating the mid-portion or trunk of the inner connection member, i.e., without encapsulating the entire joint portion. A drawback of this method however is in the increased possibility of independent rotation of the different hoses compared to prior art designs; it is believed that the external runners or bridges do not provide the stability provided by the fully encapsulating molding, i.e., that technique whereby the outer covering element encapsulates the hose connection points and the entire trunk of the inner connection member. Moreover, because the molding material must be forced through generally narrow external runners, the molding operation must take place at relatively high pressures and temperatures, resulting in increased production costs. These higher temperatures moreover result in increased cool down periods for the plastics molding material, thus further increasing production time and decreasing production efficiencies. The generally permanent external runners or bridges between hose connection points also pose the possibility of increased environmental interference, i.e., entanglement with other objects in the vicinity of the assembly.
Thus, a need exists for a durable, long-life molded hose joint assembly which is resistant to independent rotation of the individual hose members, but is efficient, economical and easy to manufacture.
Accordingly, it is a primary object of the present invention to provide a molded hose joint assembly which is efficient, economical and easy to manufacture, and minimizes the risk of independent rotation of the several hose members.
It is a further object of the present invention to provide such an assembly which can be utilized in automotive and/or industrial coolant circuit systems.
It is yet another object of the present invention to provide such a hose joint assembly which adequately addresses hose pull-off and blow-off concerns.
It is yet another object of the present invention to provide an improved method for manufacturing such hose joint assemblies, which method involves a relatively low cost alternative to prior art methods.